Air motor rotor assembly

ABSTRACT

A portable pneumatic tool including a rigid housing and pendant handle. A rotary vane-type motor including a rotor is disposed within the housing and is powered by compressed air delivered through the handle. A trigger on the handle controls the flow of air to the motor and an output spindle, driven by the motor, is adapted to have rotary tool means secured thereto, an external member is used to adjust rotor clearance within the motor.

O Umted States Patent 1151 3,642,389

Chambers et a1. Feb. 15, 1972 [54] AIR MOTOR ROTOR ASSEMBLY 2,294,805 9/1942 Robinson ..418/107 2,781,027 2/1957 Henry ....92/122 1721 Ya fl f'g mg 3,043,274 7/1962 Quackenbush ..173/163 es 3,053,236 9/1962 Self eta1 ..92/125 [73] Assignee: The Black and Decker Manufacturing 7,5717/1963 Kaman ..173/ 163 X Company, T Md, 3,123,338 3/1964 Borden.....415/503 X 3,295,262 1/1967 Brown ..173/163 X [22] Filed: Oct. 1,1969 [21] APPLNOJ 862,901 Primary ExaminerMar tin P. Schwadron AssistantExammerlrw1n C. Cohen Attorney-Leonard Bloom and Joseph R. Slotnik [52]U.S.Cl ..4l8/l07, 173/163, 308/189.1 [51] lnt.C1. ..F01c 19/00 57ABSTRACT [58] Field ofSearch ..4l8/107,131, 133,134,135,

418/173; 173/12, 163; 308/189 207 A portable pneumatic too] including arig d housmg and pendant handle. A rotary vane-type motor including arotor is disposed within the housing and is powered by compressed air[56] Reterences Clted delivered through the handle. A trigger on thehandle controls UNlTED STATES PATENTS the flow of air to the motor andan output spindle, driven by the motor, is adapted V to have rotary toolmeans secured 617,671 1/1899 Coldwell ..308/l89.1 thereto, an externalmember is used to adjust rotor clearance 638,853 12/1899 Snyder.....418/134 within the motor 1,279,268 9/1918 Coldwell ..308/189.11,422,946 7/1922 Egersdorfer ....418/134 X 9 Claims, 8 Drawing Figures o\1 J '63 Q -6l 23 PAIENTEUFEB 15 I972 3. 642.389

sum 1 or 2 INVENTORS WILLIAM W. CHAMBERS BY xgt{ ZQJ-ESTOT ATTORNEYPATENTEDFEB 15 m2 s. 642 389 sum 2 or 2 INVENTORS WILLIAM w. CHAMBERSATTORNEY SUMMARY OF THE INVENTION The present invention is directed toan improved air motor assembly which facilitates providing properclearance between the rotor and end plates after assembly of the parts.The invention includes manually manipulatable means adapted to axiallyshift the rotor relative to the end plates. The invention obviates theneed for maintaining difficult tolerances on the rotor end plates and onfit-up of the rotor bearings.

The main object of the present invention, therefore, is to provide animproved air motor rotor assembly which facilitates easily establishingproper axial clearance between the rotor and stationary end plates afterassembly of the motor parts.

Further important objects of the present invention are to provide animproved assembly of the above character which minimizes the cost anddifficulty of forming the various motor parts, and which is relativelyeasy and inexpensive to carry out and provides a durable and accurateassembly.

Other objects and advantages of the invention will become more apparentfrom a consideration of the detailed description to follow taken inconjunction with the drawings annexed hereto.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational viewillustrating a portable pneumatic tool embodying the present invention;

FlG. 2 is an enlarged view, partly in section, ofa portion of FIG. 1 andillustrating the parts prior to complete assembly;

FIG. 3 is a view similar to FIG. 2 but showing the parts fullyassembled;

FIG. 4 is an enlarged view ofa portion of FIG. 3;

FIG. 5 is a view similar to FIG. 3 but showing a modified form oftheinvention;

FIG. 6 is an enlarged sectional view of FIG. 5 taken along the line 66thereof;

FIG. 7 is a view illustrating the parts at the other end of the rotor ofFIG. 5 prior to complete assembly; and

FIG. 8 is a view similar to FIG. 7 but showing the parts fullyassembled.

BROAD STATEMENT OF THE INVENTION Broadly described, the presentinvention relates to a pneumatic motor comprising a cylinder closed atits ends by end plates, a rotor disposed for rotation within saidcylinder, said rotor having radial end faces disposed in closely spaced,sliding relation to radial faces on said end plates, resilient meansbiasing said rotor in a first axial direction, and manually operablemeans including a rigid member outside said cylinder and operablyabutting said rotor for axially adjusting said rotor in a seconddirection opposite said one direction, whereby to accurately positionsaid rotor between said end plates.

In another aspect, the present invention relates to a rotary pneumaticdevice comprising a housing, a cylindrical liner fixed within saidhousing, end plates abutting said liner at opposite ends and definingtherewith a motor cylinder, a rotor within said cylinder and havingradial faces at opposite ends in closely spaced, confronting relation torespective radial faces on said end plates, a shaft fixed to said rotor,bearing means rotatably supporting said shaft within said housing,compressible means between one of said bearings and said rotor andnormally biasing said rotor in one axial direction relative to saidliner, manually operable means including a rigid member supportedrelative to said housing and operatively adjustably abutting said rotorand adapted to shift said rotor opposite said one axial directionrelative to said liner, whereby to accurately position said rotoraxially within said cylinder and said rotor end faces relative to saidend plate faces.

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DETAILED DESCRIPTION Referring now more specifically to the drawings, aportable pneumatic device embodying the present invention is illustratedgenerally at 11 in FIG. 1 and is seen to include a rigid motor housing13 and pendant handle 15. The motor housing 13 has a rotary pneumaticmotor 17 disposed therein which is powered by compressed air deliveredfrom a source through a passageway 19 in the handle 15 (see also FIG.3). Airflow to the motor 17 is controlled by a valve trigger 21 on thehandle 15 and is exhausted from the motor housing 13 by way of apassageway 23.

As shown in FIG. 3, the motor housing 13 is sleevelike in configurationand is threaded into an opening 25 in the handle 15. The motor 17includes a cylindrical liner 27 pressed into the housing 13 with a pairof'end plates 29, 31 piloted in the housing 13 and abutting oppositeends of the liner 27. A rotor 33, which includes one or more vanes 35disposed in generally radially extending slots 37 therein, is rotatablydisposed within the liner 27 and between the end plates 29, 31. Therotor 33 has fore-and-aft shaft section 36, 38 rotatably supported byball bearings 39, 41 seated in bores 43, 45 in the end plates 29, 31,respectively. The shaft section 36 extends through an opening 47 in thefront of the housing 13 and is adapted to be connected to tool means,here, a sanding-buffing head 49.

It will be appreciated that the axial position of the rotor 33 relativeto the liner 27 and end plates 29, 31 is important. Thus, the rotor 33has radial end faces 51, 53 at opposite ends thereof which are disposedin spaced, confronting face-to-face relation to radial faces 55, 57 onthe end plates 29, 31, respectively. Motor efficiency dictates thatclearance between these faces be minimal to keep air losses to aminimum; however, rubbing contact between these faces create frictionlosses which also are undesirable.

As a practical matter, the axial dimension of the liner 27 and the rotor33 are closely controlled during manufacture. Thus, since the end plates29, 31 are located by abutment with the ends of the liner 27, accurateaxial positioning of the rotor 33 relative to the liner 27 provides thedesired relationship between the end faces 51, 55 and 53, 57. One way toachieve this would be to accurately machine the bearing recesses 43, 45;however, the bearings 39, 41 themselves have manufacturing toleranceswhich often exceed that which is acceptable for the end faces of therotor 33 and end plates 29, 31. In addition, this method requires anaccurate (and expensive) fitup of the bearings 39, 41 to the end plates29, 31 and the rotor shaft portions 36, 38 during assembly, all of whichcontributes to the overall cost of the device. The present inventionprovides a different approach, i.e., one which allows a relatively easy,inexpensive and accurate fit-up of the parts after assembly withoutrequiring expensive machining of all of these parts.

Thus, as shown in FIG. 3 and 4, the handle 15 has a recess 61 alignedwith the bore 25. A pressure plate 63 is disposed within the recess 61and has an annular lip 65 disposed to engage the outer, normallystationary race of the bearing 41. An adjustment screw 67 is threadedinto an opening 69 in the handle 15 and is positioned to engage thepressure plate 63 substantially centrally thereof so that when the screw67 is threaded inwardly of the recess 61, the pressure plate 63 pushesagainst and moves the bearing 41 toward the rotor 33.

The inner race of the bearing 41 is spaced from the rotor face 53 by arigid, annular spacer 71. Similarly, the bearing 39 is spaced from therotor face 51 by a rigid annular spacer 73 and a compressible, resilientring 75. The spacer 73 and the ring 75 have a dimensional thickness suchthat when the parts are initially assembled, the rotor 33 is positionedwith its end face 53 in engagement with the face 57 of the end plate 31while the faces 51, 55 of the rotor 33 and end plate 29, respectively,are spaced from one another. Thereafter, the screw 67 is tightened topress the plate 63 against the bearing 41 which, in turn, transmits anaxial thrust through the spacer 71, the rotor 33, and the spacer 73.This causes the resilient ring 75 to be compressed and allows the rotor33 to move axially within the liner 27. When the rotor 33 has been movedsufficiently to separate the faces 53, 57, adjustment of the screw 67 isstopped. This may be determined by manually turning the rotor shaft 36while the screw 67 is being adjusted. When the rotor shaft 36 turnsfreely, adjustment is complete. Desirably, the access opening 77 to theend of the screw 67 is then filled with, for example, a liquid solder 79after adjustment is completed so that the device is tamper proof.

A modified form of the present invention is illustrated in FIG. 5-8.There, rather than the adjustment screw 67 being threaded into thehandle 15, a nut 81 is provided within the recess 61 and is preventedfrom turning by projections 83, 85 which are received in a recess 87 inthe handle 15. in addition, after adjustment is completed, liquid solder79 or a similar material is used to fill either the opening 89 throughwhich the screw 67 extends, or the access opening in the screw 67, torender the device tamper proof.

In all other respects, the device of FIGS. 5-8 is substantially the sameas that illustrated in FIG. 1-4 and described above so that likenumerals refer to like parts.

It will be appreciated that with the adjustment arrangement of thepresent invention, the rotor 33 is accurately located axially within theliner 27 and between the end plates 29, 31. This achieved without regardfor accurate and expensive machining techniques on the end plates 29, 31and bearing recesses 43, 45 therein and without regard for inherenttolerances in the bearings 39, 41. Thus, motor efficiency is maximizedwithout contributing significantly to its cost.

While preferred embodiments of the present invention have beenillustrated and described above in detail, various additions,substitutions, modifications and omissions may be made thereto withoutdeparting from the spirit of the invention.

We claim:

1. A pneumatic motor comprising a cylinder closed at its ends by endplates, a rotor disposed for rotation within said cylinder, said rotorhaving radial end faces disposed in closely s aced, sliding relation toradial faces on said end plates, resilient means biasing said rotor in afirst axial direction, and manually operably means including a rigidmember outside said cylinder and operably abutting said rotor foraxially ad justing said rotor in a second direction opposite said onedirection, whereby to accurately position said rotor between said endplates.

2. A motor as defined in claim 1 wherein said resilient means includes acompressible ring.

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3. A motor as defined in claim 1 which includes bearing means withineach said end plate, said rotor having fore-andaft shaft sectionsrotatably supported by said bearing means, said resilient means beingpositioned between one of said bearing means and said rotor, said rigidmember operably engaging one of said bearing means, whereby to transmitaxial force through said rotor to the other of said bearing means insaid second direction, whereby to shift said rotor in said seconddirection relative to said end plates.

4. A motor as defined in claim 3 wherein said bearing means includes apairof ball bearings, said rigid member includes a pressure platebearing axially against the outer race of one of said bearings and screwmeans accessible from outside said cylinder and operable to press saidplate against said one bearing. 7

5. A motor as defined in claim 3 which includes a rigid annular spacerinterposed between each said bearing means and said rotor.

6. A rotary pneumatic device comprising a housing, a cylindrical linerfixed within said housing, end plates abutting said liner at oppositeends and defining therewith a motor cylinder, a rotor within saidcylinder and having radial faces at opposite ends in closely spaced,confronting relation to respective radial faces on said end plates, ashaft fixed to said rotor, bearing means rotatably supporting said shaftwithin said housing, compressible means between one of said bearings andsaid rotor and normally biasing said rotor in one axial directionrelative to said liner, manually operable means including a rigid membersupported relative to said housing and operatively adjustably abuttingsaid rotor and adapted to shift said rotor opposite said one axialdirection relative to said liner, whereby to accurately position saidrotor axially within said cylinder and said rotor end faces relative tosaid end plate faces.

7. A device as defined in claim 6 wherein said rigid member includes aplate within said housing and bearing axially against one of saidbearings and screw means biasing said plate toward said one bearing,whereby to shift said rotor axially relative to said liner;

8. A device as defined in claim 7 wherein said bearings include ballbearings having inner races on said shaft and outer races, said platebearing against the outer race of said one bearing.

9. A device as defined in claim 7 wherein said screw means is threadedinto said housing.

1. A pneumatic motor comprising a cylinder closed at its ends by endplates, a rotor disposed for rotation within said cylinder, said rotorhaving radial end faces disposed in closely spaced, sliding relation toradial faces on said end plates, resilient means biasing said rotor in afirst axial direction, and manually operably means including a rigidmember outside said cylinder and operably abutting said rotor foraxially adjusting said rotor in a second direction opposite said onedirection, whereby to accurately position said rotor between said endplates.
 2. A motor as defined in claim 1 wherein said resilient meansincludes a compressible ring.
 3. A motor as defined in claim 1 whichincludes bearing means within each said end plate, said rotor havingfore-and-aft shaft sections rotatably supported by sAid bearing means,said resilient means being positioned between one of said bearing meansand said rotor, said rigid member operably engaging one of said bearingmeans, whereby to transmit axial force through said rotor to the otherof said bearing means in said second direction, whereby to shift saidrotor in said second direction relative to said end plates.
 4. A motoras defined in claim 3 wherein said bearing means includes a pair of ballbearings, said rigid member includes a pressure plate bearing axiallyagainst the outer race of one of said bearings and screw meansaccessible from outside said cylinder and operable to press said plateagainst said one bearing.
 5. A motor as defined in claim 3 whichincludes a rigid annular spacer interposed between each said bearingmeans and said rotor.
 6. A rotary pneumatic device comprising a housing,a cylindrical liner fixed within said housing, end plates abutting saidliner at opposite ends and defining therewith a motor cylinder, a rotorwithin said cylinder and having radial faces at opposite ends in closelyspaced, confronting relation to respective radial faces on said endplates, a shaft fixed to said rotor, bearing means rotatably supportingsaid shaft within said housing, compressible means between one of saidbearings and said rotor and normally biasing said rotor in one axialdirection relative to said liner, manually operable means including arigid member supported relative to said housing and operativelyadjustably abutting said rotor and adapted to shift said rotor oppositesaid one axial direction relative to said liner, whereby to accuratelyposition said rotor axially within said cylinder and said rotor endfaces relative to said end plate faces.
 7. A device as defined in claim6 wherein said rigid member includes a plate within said housing andbearing axially against one of said bearings and screw means biasingsaid plate toward said one bearing, whereby to shift said rotor axiallyrelative to said liner.
 8. A device as defined in claim 7 wherein saidbearings include ball bearings having inner races on said shaft andouter races, said plate bearing against the outer race of said onebearing.
 9. A device as defined in claim 7 wherein said screw means isthreaded into said housing.